Fuel oil preheaters



May 24, 1955 M. C. CROTTY FUEL OIL PREHEATERS Filed New 26, 1951 United States Patent FUEL OIL PREHEATERS Michael C. Crotty, Flushing, N. Y.; Mary A. Crotty, executrix of said Michael C. Crotty, deceased, assignor to Crotty Manufacturing Corporation, Flushing, N. Y., a corporation of New York Application May 26, 1951, Serial No. 228,518

Ciaiins. (c1. 122--1 The present invention relates to a fuel oil preheater for a fuel oil fired furnace having an auxiliary boiler or boiler amplifier.

In my patents, Nos. 2,386,842 and 2,420,231 and my pendingapplication for patent filed September 6, 194-9, S. N. 116,077, now abandoned, I have described and claimed several forms of boiler amplifiers of the water Wall type. In some of these the water to be heated in the auxiliary boiler is carried through annular tubes or annular pipes and headers surrounding the combustion area but within the walls of the combustion chamber of the auxiliary boiler. In a third form disclosed and claimed in my pending application, the water is carried through a cylindrical jacket surrounding the outer wall of the combustion chamber. The present invention is particularly applicable to and an improvement upon the arrangement of the last described form.

In a fuel oil fired boiler it has long been recognized to be of advantage particularly when fuel oils of high viscosity are used to preheat the fuel oil before introducing it to the burner and thus reduce its viscosity to insure instantaneous ignition and complete combustion. However, diificuties have been encountered in most arrangements of fuel preheaters due to the deterioration of the heating surfaces and the resulting leakage of the fuel oil into the water system of the boiler with the attendant interruption of operation of the boiler and necessity for protracted lay-oft for a complete cleaning of the boiler and its tubes to remove the elfects of the fuel oil.

The deterioration and resultant rupture of the wall surface of the fuel oil preheaters of the prior art have arisen from the fact that they are usually of the shell and tube type, generally placed in the boiler itself and thus having relatively very thin walls. In the present invention, advantage is taken of the use of a relatively thick wall as the heating surface.

In these prior art devices, the temperature to which the fuel oil can be heated is limited to below 212 F. since the heating agent is the boiler water. In the ar rangement of the present invention, since the fuel oil derives its heat from a water superheater in which the water is above 212 F., it may be preheated to a higher temperature.

It is an object of the present invention to provide a combination auxiliary boiler and fuel oil preheater.

It is a further object of the-present invention to provide a fuel oil preheater for use with an auxiliary boiler which overcomes the disadvantages of the fuel oil preheaters of the prior art.

It is a further object of the present invention to provide a fuel oil preheater in which the fuel oil can be heated to temperatures higher than those previously achieved in such apparatus.

It is a further object of the present invention to provide a fuel oil preheater which uses the heat which would otherwise be lost by radiation from the outer wall of a Water type auxiliary boiler or boiler amplifier.

It is a further object of the present invention to provide a fuel oil preheater arranged to have simple and economical connections to the burner and boiler.

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It is a further object of the present invention to provide a fuel oil preheater of simple, sturdy and ecornical construction.

It is a further'object of the present invention to provide a fuel oil preheater of simple, trouble-free and ecoomical operation.

Further objects and advantages of the present invention will be apparent by reference to the specification and appended drawings in which:

Fig. 1 representsa front elevation of the fuel oil preheater of this invention in place on the auxiliary boiler attached to the main boiler with part of the fuel oil preheater in section, and

Fig. 2 represents a side view of the fuel oil preheater of this invention in place on the auxiliary boiler and attached to the main boiler with a portion cutaway and a portion in section.

Referring to the drawings, 1 indicates the main boiler of the furnace, 2 indicates a pipe through which boiler Water is withdrawn by action of pump 3 and delivered through pipe 4 to the bottom of auxiliary boiler 5. Auxiliary boiler 5 consists of two concentric cylinders 6 and 7 which are closed at the ends as shown to hold the boiler water delivered through pump 3. An oil burner 8 projects flame into the combustion chamber defined by the interior wall 6 of'the auxiliary boiler 5 through end plate 9 and through throat 10. The combustion chamber of auxiliary boiler 5 communicates at itsopen end with the combustion chamber of main boiler 1. Primary air for combustion is introduced through oil burner 8 which may be equipped with a blower for atomizing the fuel or with any other suitable device for forcing air through oil burner 8 into the combustion chamber. Secondary air is admitted to the wind box 11 and thence to the furnace and burner 3 through an intake 11a. Wind box 11 is of circular cross section and is defined by end plate 9 and side walls 12. It includes air intake 11a and throat 10. As the air enters through intake 11a it flows around throat 10 and is delivered to the combustion chamber-of the auxiliary boiler from'all sides of wind box 11, thus attaining a more efficient combustion than would be attained if the air were not so introduced. The admission of air to wind box 11 is controlled and regulated by adjustable damper 13.

Throat 10 is provided with a collar 14 which is circular in cross section and which consists of a suitable material to reflect heat. It is dished out to a saucershaped formation around the fire nozzle of burner 8'. Collar 14 is provided with a plurality of auxiliary air inlets 15.

Formed as an ,arcuate section and attached by' any desired and suitable means to outer wall 7 of auxiliary boiler 5'is fuel oil preheater 16. This comprises concentric arcuate sections 7 and 17 forming respectively the inner and outer walls of oil fuel preheater 16. End walls 18 and 19 close fuel oil preheater16.

As shown in Fig. 2, fuel oil preheater 16 may extend the length of auxiliary boiler 5 and as shown in Fig. 1 may subtend an angle of about around auxiliary boiler 5. It is to be understood, however, that when desirable fuel oil preheater 16 may be made shorter than auxiliary boiler 5 and may extend around it to a greater or lesser extent than shown in Fig. 1.

Fuel oil preheater 16 is provided with a series of finlike partitions 21 which extend lengthwise of fuel oil preheater 16 for nearly its entire length but leave passages between their ends and front and back walls 22 and 23 respectively of fuel oil heater 16.

Fuel oil preheater 16 is provided with an oil inlet pipe 24 leading from the oil supply (not shown) and an oil outlet pipe 25 connected through valve 26 to burner '8.

In operation, water is drawn from main boiler 1 by pump 3 through pipe 2 and then pipe 4 to auxiliary boiler 5 wherein it is heated by the flame in the combustion chamber. It then rises under the pressure of pump 3 through pipe 27, pressure drop device 28 and enters main boiler 1 at the water line.

The fuel oil is led by gravity or a pump (not shown) to oil inlet pipe 24. It then passes through fuel oil preheater 16 following a labyrinthine path back and forth between the front and back of fuel oil preheater 16 as determined by partitions 21. In doing this, it takes up heat from outside wall 7 of auxiliary boiler 6 and finally goes to burner 8 through pipe 25 and valve 26.

Pressure gauge 29 and thermometer 30 are inserted in auxiliary boiler 16 for obvious purposes which need not be discussed here.

I claim:

1. In combination with a main boiler an auxiliary boiler in which said auxiliary boiler comprises a cylindrical combustion chamber having a fuel oil burner at one end and being open at the other end to the combustion chamber of the main boiler and a cylindrical water superheater surrounding said combustion chamber of said auxiliary boiler, a fuel oil preheater comprising an enclosed space formed by a portion of the external wall of said water superheater and an outside wall of 'steel plating concentric with said outside wall of said water superheater but radially spaced therefrom and shaped at its edges to meet and form a tight seal with said outside wall of said water superheater and partitions therein lying substantially in radial planes containing extensions of radii of said combustion chamber and of such length to form passages between alternate ends of said partitions and the respective end walls of said fuel oil preheater, an inlet connection to said fuel oil preheater and a connection therefrom to said oil burner.

2. In combination a main boiler, an auxiliary boiler comprising a cylindrically formed combustion chamber having a fuel burner mounted in a closed end thereof and opened at the other end to the combustion chamber of the main boiler and a water superheater formed to extend around the circumference of the outer wall of said auxiliary boiler combustion chamber and along its length said water superheater being made of concentrically arranged steel plating, means for circulating under pressure water from the lower portion of said main boiler to the lower portion of said water superheater, through said water superheater, and in an upwardly direction back to said main boiler at the water level therein, means for the reduction of pressure at the point of re-entry of said water into said main boiler and a fuel oil preheater disposed over a portion of the external circumference of said water superheater and extending substantially the length thereof in which the inner wall of said fuel oil preheater is formed by a portion of the outer wall of said water superheater, an inlet connection to said fuel oil preheater and a connection therefrom to said oil burner.

3. In combination a main boiler, an auxiliary boiler comprising a cylindrically formed combustion chamber having a fuel burner mounted in a closed end thereof and open at the other end to the main boiler combustion chamber and a water superheater formed to extend around the circumference of the outer wall of said auxiliary boiler combustion chamber and along its length, said water superheater being made of concentrically arranged steel plating, pipe connections between the water compartment of said main boiler and said water superheater forming a closed circulatory system, means associated with said pipe connections to maintain sufficient pressure on said water while in said water superheater and pipe connections to prevent separation of steam therefrom, pressure release means to allow the escape of steam from said water at the point where it re-enters said main boiler and a fuel oil preheater disposed over a portion of the external circumference of said water superheater and extending substantially the length thereof in which the inner wall of said fuel oil preheater is formed by a portion of the outer wall of said water superheater, an inlet connection to said fuel oil preheater and a connection therefrom to said oil burner.

4. In combination a main boiler, an auxiliary boiler comprising a cylindrically formed combustion chamber having a fuel burner mounted in a closed end thereof and opened at the other end to the combustion chamber of the main boiler and a water superheater formed to extend around the circumference of the outer wall of said auxiliary boiler combustion chamber and along its length said water superheater being made of concentrically arranged steel plating, means for circulating under pressure water from the lower portion of said main boiler to the lower portion of said water superheater, through said water superheater, and in an upwardly direction back to said main boiler at the water level therein, means for the reduction of pressure at the point of re-entry of said water into said main boiler, a fuel oil preheater surrounding a portion of the outside of said water superheater and being formed by a portion of the outer wall of said water superheater and a concentrically, but radially spaced steel plate shaped at its edges to meet and form a tight seal with said outer wall of said water superheater, partitions in said fuel oil preheater defining a labyrinthine path for the circulation of fuel oil therein from the top of said fuel oil preheater to the bottom thereof and a pipe connection from said fuel oil preheater to said burner and an inlet connection to the top of said fuel oil preheater.

5. In combination a main boiler, an auxiliary boiler comprising a cylindrically formed combustion chamber having a fuel burner mounted in a closed end thereof and open at the other end to the main boiler combustion chamber and a water superheater formed to extend around the circumference of the outer wall of said auxiliary boiler combustion chamber and along its length, said water superheater being made of concentrically arranged steel plating, pipe connections between the water compartment of said main boiler and said water superheater forming a closed circulatory system, means associated with said pipe connections to maintain sufiicient pressure on said water while in said water superheater and pipe connections to prevent separation of steam therefrom and pressure release means to allow the escape of steam from said water at the point where it re-enters said main boiler, a fuel oil preheater surrounding a portion of the outside of said water superheater and being formed by a portion of the outer wall of said water superheater and a concentrically, but radially spaced steel plate shaped at its edges to meet and form a tight seal with said outer wall of said water superheater, partitions in said fuel oil preheater defining a labyrinthine path for the circulation of fuel oil therein from the top of said fuel oil preheater to the bottom thereof, a pipe connection from the bottom of said fuel oil preheater to said burner and an inlet connection to the top of said fuel oil preheater.

References Cited in the file of this patent UNITED STATES PATENTS 664,186 Strobel Dec. 18, 1900 757,949 Mylin et al Apr. 19, 1904 785,009 Liebentritt Mar. 14, 1905 1,029,300 Jones June 11, 1912 2,360,408 Dunn et al Oct. 17, 1944 2,386,842 Crotty Oct. 16, 1945 2,406,604 I-Iolthouse Aug. 27, 1946 2,420,231 Crotty May 6, 1947 2,457,022 Yula Dec. 21, 1948 2,524,608 Stautfer Oct. 3, 1950 FOREIGN PATENTS 15,315 Great Britain June 30, 1911 

